Nate Berg is a freelance reporter and a former staff writer for CityLab. He lives in Los Angeles.
How urban design affects serious traffic accidents among our oldest populations.
Strip malls, big-box shopping centers and arterial roads are some of the most common elements of North American communities. They're in cities and suburbs all over the continent. They may also be causing senior citizens to crash their cars or get hit by cars at significantly higher rates than other parts of town.
According to a new report [PDF] from the Texas Transportation Institute at Texas A&M University, the nearly ubiquitous giant-parking-lot-plus-giant-retail outlet is associated with higher risks of injurious and deadly traffic accidents among people 75 and older. Seventy-five is the age when older adults become substantially more likely than other age cohorts to experience injury or fatality as a result of a traffic accident, mainly because of their increasingly frail bodies, but also due to their waning hearing and eyesight.
Using data from 2003 through 2007 from the Texas Department of Transportation, researchers Eric Dumbaugh, Yi Zhang and Wenhao Li explored KSI crashes – those where people are either killed or severely injured – involving pedestrians or motorists aged 75 or older in San Antonio. Combining this data with street and land use information, the researchers were able to identify when certain roadways and urban development types have created greater incidence of traffic accidents among this age group.
Of the 26,533 crashes involving adults 75 and older during this five-year period, 3,576 are considered KSI. Most of those were drivers or passengers in motorized vehicles.
Among motorists, crashes and injuries increased only about 0.4 percent when there were more intersections in an area. But in areas with strip malls, crashes increased 2.5 percent. In areas with big box shopping centers, crashes increased 7.2 percent. Pedestrian-scaled retail centers, on the other hand, were found to correspond with a 2.9 percent decrease in crashes. Crashes were higher on arterial roads and lower in areas with higher amounts of slower side streets.
For older pedestrians and cyclists, arterial thoroughfares and big box shopping centers were associated with significant increases in crashes – 28 percent and 8.6 percent, respectively.
The research suggests that a more substantial network of slower, narrower streets would benefit areas with high concentrations of older adults. And though this would mean more intersections – shown in the report to slightly increase the amount of crashes – the safety improvement would "greatly outweigh" any disadvantages, according to the authors.
It's expected that nearly 50 million people will be aged 75 or older in the U.S. by mid-century. Urban designers may want to start un-designing strip malls, big boxes and super fast streets now before the crush. The reduction of these types of urban design elements may help to prevent the premature death of seniors, today and in the future.